Unit Converter
Convert length, weight, temperature, volume and speed instantly — metric to imperial made easy.
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Popular conversions
How to Use the Unit Converter
Pick a category — length, weight, temperature, volume, or speed — then type a value and choose your "from" and "to" units. Results update live as you type, the exact formula shows under the answer, and the ⇄ button flips the direction instantly. The popular-conversions table below each category is clickable: hit "Use" to load any conversion into the calculator.
Categories Covered
- Length: millimeters to miles — mm, cm, m, km, inches, feet, yards, miles.
- Weight: grams to tons — g, kg, ounces, pounds, stone, metric tons.
- Temperature: Celsius, Fahrenheit, Kelvin — converted with the proper offset formulas, not just multiplication.
- Volume: milliliters to gallons — ml, liters, teaspoons, tablespoons, fluid ounces, cups, pints, quarts, gallons.
- Speed: m/s, km/h, mph, ft/s, knots.
Metric vs Imperial Systems
The metric system is decimal by design: 1,000 millimeters in a meter, 1,000 meters in a kilometer, 1,000 grams in a kilogram. Conversions are just moving a decimal point. The imperial system grew organically: 12 inches in a foot, 3 feet in a yard, 1,760 yards in a mile, 16 ounces in a pound. Every imperial conversion is a different arbitrary number — which is exactly why converters exist.
Most of the world runs on metric; the US, UK (partially), and a few others mix both. Science, medicine, and international trade are metric throughout. When a recipe, a spec sheet, or a road sign uses the "other" system, convert — don't guess.
Most Popular Conversions
| Conversion | Factor | Example |
|---|---|---|
| cm → inches | ÷ 2.54 | 100 cm = 39.37 in |
| kg → pounds | × 2.20462 | 70 kg = 154.32 lb |
| °C → °F | (× 9/5) + 32 | 20°C = 68°F |
| km → miles | × 0.621371 | 10 km = 6.21 mi |
| liters → gallons | × 0.264172 | 5 L = 1.32 gal |
A Note on Accuracy
Conversion factors between metric and imperial are exact by definition: 1 inch is defined as 2.54 cm, 1 pound as 0.45359237 kg. There's no measurement error in the factor itself — any rounding happens only in the displayed digits. The calculator computes at full precision and rounds the display, so chaining conversions won't drift. For temperature, remember the offset: converting °C↔°F isn't a multiplication, it's a multiplication plus 32 — the classic source of "close but wrong" mental math.
My saved numbers reuse them in any calculator
Save a number once — like your rent or hourly rate — then just type its name instead of the number, in any calculator here. You can also type formulas like 5000 * 1.1 right into any box.
Saved only in this browser — nothing is sent to us.
Frequently Asked Questions
How do I convert metric to imperial?
Multiply by the conversion factor: centimeters × 0.3937 = inches, kilograms × 2.20462 = pounds, kilometers × 0.621371 = miles. This converter applies the exact factors instantly.
What are the most common unit conversions?
cm to inches (÷ 2.54), kg to lbs (× 2.20462), °C to °F ((× 9/5) + 32), km to miles (× 0.621371), and liters to gallons (× 0.264172). The quick chart below covers all of them.
Is this converter accurate?
Yes — it uses exact defined conversion factors (1 inch = 2.54 cm exactly, 1 lb = 0.45359237 kg exactly). Results are rounded for display but computed at full precision.
How many centimeters are in an inch?
Exactly 2.54 centimeters per inch, by international definition since 1959. So 10 inches = 25.4 cm.
How many kilograms are in a pound?
Exactly 0.45359237 kilograms per pound. So 1 kg = 2.20462 lbs, and 150 lbs ≈ 68.04 kg.